The following essay is part of a series in which dozens of women will reveal what women they most admire. The series is part of “Women Rule,” a unique effort this fall by POLITICO, Google and The Tory Burch Foundation exploring how women are leading change in politics, policy and their communities. See more essays here.

Before I met Kati Haycock, I didn’t know women could be that way.

Name the adjective — assertive, brash, straightforward, whatever — I grew up being told women weren’t supposed to be that way. In fact, that was a sort of mantra I heard from my mom, who is Korean and immigrated here with my dad just four years before I was born. “Girls aren’t supposed to act like that,” she’d say time and again.

I was in my 30s and still hearing that message echo in my head.

Then I met Kati.

Kati is one of our nation’s most passionate advocates for kids. She has run The Education Trust since 1991 and, on top of the incredible work of that organization, does so much more for public education in our country, serving as a director of The Carnegie Foundation for the Advancement of Teaching as a commissioner for the Robert Wood Johnson Foundation, a member of the U.S. Secretary of Education’s Commission on the Future of Higher Education — and more.

I recently pulled up something she wrote in 1998 about how our public school teachers are trained and chosen. “We’ve not been willing to set nearly as high standards for teachers as we’re now setting for kids,” she wrote, pointing out a lack of teachers able to teach math or willing to teach in at-risk neighborhoods or skilled in dealing with students with special needs. “We’re producing too few teachers who have the level of knowledge it takes to teach students to high standards.” That kind of straight talk inspired me as I was getting The New Teacher Project up and running. It’s why I asked Kati to serve on the TNTP board of directors.

What’s also so inspiring about Kati is her singular focus on closing the achievement gap that exists between white kids and children of color and those from households with lower income. She lasers in on that objective, and it permeates everything she does. There’s nothing more important to improving public education and ensuring that every child here has an equal shot at the American dream.

One of the reasons I admired Kati so much when I was younger was not that she is assertive and swears like a sailor — though those things are true. I admired her because she is those things, and it still works. She can be aggressive, but her colleagues and even opponents still respect her and work with her.

She taught me that you can be unapologetic and still professional, a little abrasive but still effective.

She doesn’t sugarcoat it — with anybody. In 2007, when D.C.’s newly elected Mayor Adrian Fenty offered me the opportunity to run the District’s public school system as its chancellor, Kati was the first person to tell me “No freaking way!”

She was one of my most trusted confidantes, so her opinion gave me pause.

“You’ll get slaughtered by the racial politics,” she told me. “You know this city and its school district are on a completely different level of dysfunction. Don’t do it.”

I took the job anyway — and Kati couldn’t have been more supportive. I took Kati’s lessons with me. And I used them. She’d taught me to be fearless and speak my mind. Those are tools I needed to tackle the challenges of the worst big-city public school district in the country. They’re tools I use today confronting the differences between adults’ needs and kids’ needs in our public schools.

Kati Haycock was, and continues to be, my role model.

Michelle Rhee is founder of StudentsFirst, a grass-roots education reform advocacy organization, and author of “Radical: Fighting to Put Students First.”